Increasing Incidence of Type 1 and Type 2 Diabetes Among Canadian Children.

Background: Diabetes mellitus is one of the most common pediatric chronic illnesses. Although a rising incidence of childhood type 1 diabetes (T1D) has frequently been documented, an almost 400-fold variation in incidence has been seen worldwide. We aimed to describe the trends in incidence of diabetes (type 1, type 2, all types) among children and adolescents living in the Greater Montréal area of Québec, Canada.

Methods: Using health administrative data (Québec Integrated Chronic Disease Surveillance System) and medical records from the 3 major pediatric diabetes centres in the Greater Montréal area, we conducted serial cross-sectional studies of children aged 1 to 15 years during the period from 2002 to 2010. We conducted a trend analysis of diabetes incidence over time using multivariate Poisson regression models.

Results: We identified 696 new cases of diabetes between 2002 and 2010. The age-standardized incidence of diabetes (all types) increased from 16.3 (95% confidence interval [CI], 12.4 to 21.2) to 27.8 (95% CI, 22.5 to 34.0) per 100,000, with annual incidence increasing, on average, by 5.2% per year (adjusted rate ratio [aRR], 1.052; 95% CI, 1.022 to 1.083). This was driven predominantly by the T1D annual increase of 5.4% (aRR, 1.054; 95% CI, 1.023 to 1.086). A low number of incident cases of type 2 diabetes limited trend analysis in this group. There were no significant interactions between year and sex or age.

Conclusions: The annual incidence of T1D is increasing in Québec children and does not vary by sex or age. Further research into etiologic factors is indicated.